Goal:
    z : Z  k : t  H : Some z = k
  ============================
   (None = k \/ Some z = k)


DEBUG:Going to execute:
Ltac.right; t_tauto_intuit
Level 1: Backtrace:

Proof is not complete.
Level 2: Backtrace:

Proof is not complete.
Level 1: Backtrace:

Proof is not complete.
Level 1: Backtrace:

Proof is not complete.
Level 1: Backtrace:

Proof is not complete.
Level 1: Backtrace:

Proof is not complete.
Level 1: Backtrace:

Proof is not complete.
Level 1: Backtrace:

Proof is not complete.
Level 1: Backtrace:

Proof is not complete.
Level 2: Backtrace:

Proof is not complete.
Level 1: Backtrace:

Proof is not complete.
Level 2: Backtrace:

Proof is not complete.
Level 2: Backtrace:

Proof is not complete.
Level 1: Backtrace:

Proof is not complete.
Level 3: Backtrace:

Proof is not complete.
Level 2: Backtrace:

Proof is not complete.
Level 1: Backtrace:

Proof is not complete.
Level 2: Backtrace:

Proof is not complete.
Level 1: Backtrace:

Proof is not complete.
Level 1: Backtrace:

Proof is not complete.